The recovery of reactive components from polyurethane scrap material, such as polyurethane foam, has been the subject of considerable inventive effort. Despite this effort, polyurethane foam still is often disposed of commercially in land fill. It is apparent that a need exists for expedient methods and aparatus for processing such materials so as to recover reuseable reactants including polyol and diamine and avoid the necessity for alternative disposal techniques.
Among the approaches proposed for recovery, hydrolysis is known to offer certain advantages, particularly if it can eliminate or reduce a need for larg scale use of organic solvents. The low thermal conductivity of materials such as polyurethanes, however, normally is a limitation in gaseous hydrolysis methods due to extended warm-up periods required before conditions satisfactory for hydrolysis are obained. Such warm-up periods are troublesome even though catalysts may speed the decomposition reaction after hydrolytic decomposition conditions are attained.
Another difficulty encountered with known hydrolytic decomposition methods is that of contamination of recovered polyol with water and amine. Seemingly low levels of water and amine in recovered polyol can markedly reduce the value of the polyol. The value of the polyol, understandably, is integral factor for determining competitiveness of the hydrolytic process.
The invention overcomes the aforementioned deficiencies of prior art hydrolytic recovery processes by providing a hydrolytic decomposition process which allows rapid heating of porous polyurethane foams, such as open cell polyurethane foams and like materials, and separation of high quality polyol and diamines therefrom.